Orchard arsenic and changing land use in the Great Valley, Virginia and West Virginia

Residential redevelopment of former agricultural lands that may be contaminated
by arsenical pesticides is an environmental concern in the rapidly growing
northern Virginia-West Virginia region, due to possible increased risk of human
exposure to arsenic and other toxic metals, as well as the potential for contamination
of the vulnerable karst groundwater aquifer that is extensively used as a drinking
water source. (A map of the Great Valley physiographic province is shown in USGS
Circular 1166, figure 3.)

The objective of this study was to evaluate whether the use of arsenical pesticides
on orchard crops during the 1920s to 1960s in the Great Valley area of Virginia
and West Virginia has resulted in significantly elevated concentrations of
arsenic and other metals
in the
soils of former apple orchards, or in stream sediments from drainage basins
containing orchards.

The study conducted a review of existing data and initiate a soil, sediment,
water, and biological media sampling project to evaluate the environmental
significance of arsenical pesticide residues in the karst environment of the
northern Great Valley, Virginia and West Virginia.

This study addressed the following research questions:
1. Do the soils in and adjacent to orchard sites where arsenical pesticide was
used contain elevated concentrations of arsenic and other metals relative to
likely background conditions?
2. Based on historic land use, agricultural census, and other data, what is the
likely extent of potential contamination from arsenical pesticide residues in
the region?
3. Using EPA and other risk-based concentration criteria, do the sediments and waters in the region poste a risk to human health or ecosystem function?
4. Does redevelopment of former orchard sites as residential property increase
the dipsersal of contaminated sediment and increase the exposure of humans and
wildlife to arsenic and other toxic metals?
5. Can periodic cicadas be used as an easily sampled biomonitor measuring
bioavailability
of pesticide residues in soils?
6. Do the concentration levels of arsenical pesticide residues in periodic
cicadas emerging from contaminated orchard sites pose a dietary threat to birds
and other
wildlife that preferentially feed upon cicadas during emergence events?